Motion estimation is an important step in video compression. To describe the frame-by-frame changes in terms of motion vectors, the function block of motion estimation in a video codec receives from the source a frame to be processed and recovers the previous frame from the frame buffer, the previous frame having left the source. The majority of the frame buffer's limited outbound bandwidth is thus often preoccupied, impairing the performance of the codec. Furthermore, video codecs are put on more stringent requirements by the three-dimensional (3D) video extensions to standards such as AVC (Advanced Video Coding) and its successor HEVC (High Efficiency Video Coding), where it is required that depth maps, which describe the distance of each image block in a video to the camera, be compressed parallel to ordinary captured images.